This invention is in relation to a transmitter/receiver circuit for signal transmission over power wiring.
In the transmitting section of such a power wiring transmission system, the lower the output impedance, the better, for effective superimposing of signals on the distribution line. However, attachment of low impedance loads to the distribution line should be prevented and carrier leakages due to the efffects of high level noise (thyristor noise etc.) on the input side must also be prevented during transmission breaks. On the one hand, higher input impedance is better, from the standpoint of the receiving section, to prevent drops in signal level at the receiving point and also to prevent loading when a number of receiving units are connected.